1. Field of the Invention
The present invention relates to the production of 1,7-octadiene by hydrodimerizing butadiene.
2. Description of the Prior Art
Hydrodimerizing butadiene with formic acid and palladium catalyst is known. Wright in U.S. Pat. No. 3,732,328 issued May 8, 1973, prepares mixtures of octadienes by reacting butadiene in the presence of a palladium compound, a polar solvent, a reducing agent and a tertiary phosphine. Wright in U.S. Pat. No. 3,832,199, issued July 9, 1974, prepares mixtures of octadiene by reacting butadienes in the presence of a palladium compound, a non-polar solvent, a reducing agent and a tertiary phosphine. Wright in British Pat. No. 1,341,324 issued Dec. 9, 1973 discloses processes similar to above. Gardner et al, Tetrahedron Letters No. 2, pp. 163-164 discloses the production of mixtures of octadiene by reacting butadiene in the presence of palladium salts, or organic base, formic acid and a phosphine. Roffia et al, Journal of Organometallic Chemistry, 55 (1973) 405-507 utilizes a phosphine-zero valent palladium complex catalyst in benzene in the presence of formic acid to dimerize butadiene.
The prior art has not recognized the advantages of utilizing mixtures of different tertiary organo phosphine compounds to enhance catalyst activity.